Cranial Imaging Before Lumbar Puncture in Adults With Community-Acquired Meningitis: Clinical Utility and Adherence to the Infectious Diseases Society of America Guidelines.

BACKGROUND.: The Infectious Diseases Society of America (IDSA) guidelines delineate criteria for the use of computed tomography (CT) scan of the head before lumbar puncture (LP) in adults with community-acquired meningitis (CAM). There are limited data to document adherence to these guidelines and assess the clinical utility of brain imaging. METHODS.: This was a retrospective analysis from January 2005 to January 2010 in Houston, Texas. RESULTS.: Among 614 adults with CAM, 407 patients (66.3%) did not have an indication for a head CT scan and 207 (33.7%) did. Patients with a CT scan indication were older, had more comorbidities, were sicker, and had more urgent treatable etiologies and adverse clinical outcomes (P < .001). A CT scan was ordered before the LP in 549 patients (89%). Overall, clinicians did not adhere to clinical guidelines in 368 of 614 (60%) subjects. A CT of the head was ordered when not indicated in 355 of 549 patients (64%), and not done when indicated in 13 of 207 patients (0.6%). CT of the head revealed intracranial abnormalities in 35 of 193 patients (18.1%) with an indication for brain imaging, compared with only 2 of 356 (0.05%) with no indication (P < .05). Major intracranial findings were seen in only 15 of 549 (2.7%) patients, all with an indication for brain imaging. Furthermore, only 8 patients had abnormalities that affected clinical management. CONCLUSIONS.: Most clinicians do not adhere to IDSA guidelines, delaying diagnostic LP and increasing costs. Usefulness of head CT in patients with CAM without an indication for imaging is limited and has no impact in clinical management.